COLORADO SPRINGS, Colo. — Democrat Barack Obama on Wednesday showcased plans to encourage volunteerism by Americans, his latest push to woo conservative voters also sought by rival John McCain. The Republican, meanwhile, was traveling in South America promoting politically risky free trade at a time when Americans are grappling with the country's economic woes.

Obama, who has spent much of the week leading up to the U.S. Independence Day holiday on Friday speaking about patriotism, spoke in Colorado Springs, Colorado, a bastion of conservativism. His push has been aimed at fostering a middle-of-the road political persona to counter Republican attempts to label him as too liberal.

Obama's plan, which encourages Americans to serve at home and abroad to address issues such as education and climate change, is part of an overall agenda to press Americans into service to show "the world the best of our nation," according a statement from his campaign.

Obama said the quiet weekend following Friday's Fourth of July celebrations would be a good time for every person to consider how they can contribute "to our most pressing national challenges" — whether in the military, overseas or just next door.

On Monday he defended his own patriotism and a day later promised to engage grass roots religious groups with federal money if they tackle the country's social ills. His appearance Wednesday in the Colorado city home to the U.S. Air Force Academy reinforce those themes.

Obama has already promised college tuition grants to those who commit to national service after graduation.

On Wednesday, he repeated calls for American sacrifice as president and, to put teeth behind that, he proposed the expansion of government national service programs, first unveiled in Iowa in December, that would cost $3.5 billion a year. His campaign said he would fund the spending with some of the savings from ending the war in Iraq and by canceling a new tax break for multinational corporations.

McCain was in Colombia, where he praised President Alvaro Uribe's efforts to stabilize the country and reduce the flow of drugs into the United States. He said Plan Colombia, a program the U.S. government launched 10 years ago to reduce cocaine production in the country, along with other efforts, had substantially curbed cocaine supplies and raised the price of the drug on U.S. streets.

The Arizona senator also is a strong supporter of a proposed free trade agreement between the U.S. and Colombia and planned to promote it and other hemispheric trade deals during the visit. Obama opposes the Colombian agreement, which has stalled in the House over concerns about continuing intimidation and violence against labor leaders in the country.

Obama has also vowed to re-negotiate the North American Free Trade Agreement with Mexico and Canada, a deal critics say is responsible for the disappearance of American jobs. McCain supports the pact while acknowledging it is a tough sell in important U.S. states like Ohio, Pennsylvania and Michigan that have been particularly hard hit by the loss of manufacturing jobs.

While McCain was in Latin America, one of his Republican colleagues in the Senate told a U.S. newspaper that he saw McCain roughly grab an associate of Nicaraguan President Daniel Ortega and lift him out of his chair during a diplomatic mission to the Central American nation in 1987. McCain firmly denied it Wednesday.

"I don't know what had happened to provoke John, but he obviously got mad at the guy ... and he just reached over there and snatched ... him," Sen. Thad Cochran, a Mississippi Republican, said in an interview with the Sun Herald in Biloxi, Mississippi.

When asked about the article, Cochran spokeswoman Margaret McPhillips told The Associated Press: "I think his quotes in the Sun Herald speak on that issue."

McCain told reporters in Colombia that Cochran's story was "simply not true."

"I had many, many meetings with the Sandinistas," McCain said. "I must say, I did not admire the Sandinistas much. But there was never anything of that nature. It just didn't happen."

A former McCain aide who was along on the mission, Lorne Craner, also said he didn't recall an incident like that.

Cochran has complained about McCain's temper before and the two senators have battled over spending issues for years.

McCain was continuing his Latin America trip Wednesday. He was meeting with other government officials and business leaders and taking a tour of a Naval base in Colombia before departing for Mexico City in the evening.

Meanwhile, Obama drew unexpected attention when he said Tuesday that he would expand federal payments to religious groups that are tackling America's social problems — a position that could alienate some in his Democratic base who see the move as an abrogation of America's constitutional separation of church and state.

Obama has also staked out other positions that may appeal more to independent and centrist voters, recently criticizing a Supreme Court decision that struck down a state death penalty law for child rapists and supporting the high court's reversal of a gun law ban.

Taken as a whole, the positions suggest Obama may see the possibility of picking up some conservative evangelical Christian voters.

During a visit to a community ministry in Zanesville, Ohio, that operates a food bank and provides clothes, Obama said Tuesday that faith "can be the foundation of a new project of American renewal. And that's the kind of effort I intend to lead as President of the United States."

Obama said he would not withhold federal money from religious organizations that restrict hiring to members of that particular faith, so long as there was no such discrimination in employing workers specifically involved in programs funded by Washington.

Rev. Barry Lynn, executive director of Americans United for Separation of Church and State, said Obama's plan would only expand programs that he said undermined civil rights and civil liberties.

"I am disappointed that any presidential candidate would want to continue a failed policy of the Bush administration," he said. "It ought to be shut down, not continued."

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